Accuracy issue with DPMS .308

[para1505]

This is a new DPMS .308 with a 18" DPMS barrel 1/10 twist. I've got a 100 rounds through it. Using 155 GB Scenar. 175 SMK and Hornady 178 BTHP using CFE 223. 2" is the smallest group I've been able to get out of it.
I have always shot bolt guns in long range so have no experience trying to accurize a AR platform.
Also do you think I just need to break it I'm more or do I have an issue.

 

[hlee]

Have you tried any factory loads, or did you go straight to hand loads? I ask because my DPMS LR308 shoots both Federal Gold Medal match (FGMM) 168 SMK and Hornady Match 168 AMAX and ELD-M very well- sub MOA. Federal Fusion 168 shot like a shotgun. Others were just meh. I have also found that seating depth; with hand loads, varget, and ELD-Ms plays a pretty big role in group size.

With my gun (2010/11 vintage), I shot 40 rounds of Federal fusion through it, seeing groups that could barely be covered with a ball cap. I switched to Hornady match and the next 5 shots were sub MOA. Factory barrels can be something of a crap shoot, so break in may or may not be necessary. I don't think it was in my case.

FGMM is a known quantity. Buy a couple of boxes and see what it does before you run head long down the "Accurizing" rabbit hole...

 

[para1505]

Think I'll try that sounds like good advice

 

[bunsen27]

I'd start with the Federal GMM as a baseline.

Another fairly universal accuracy load is:

168gr SMK or Nos CC
LC brass
WLR
~41.5gr IMR-4895 [the next node up is ~43.5gr]
COL= 2.800

 

[davsco]

yeah fgmm 168 or 175. how crappy is the trigger? when you dry fire are you easily staying right at the center of the target at 100yds? if not, drop in a nice two stage such as geissele ssa-e. do you have a bipod on front and rear bags, is the rifle rock-solid steady before you take the shot?

 

[wadebrown]

Have someone else shoot it, ideally someone who shoots a 308 AR well, especially if you are new to large frame ARs, this is what I recommend someone do after checking the rings and scope. Trying out FGMM is a great idea also, if it does not shoot FGMM well it probably does not shoot much of anything well. FGMM is kind of magic in how it shoots so well in so many different guns, it just works, there are many theories on why it does. I have bought a number of DPMS rifles and had mixed results now I build my own uppers than I have control over what barrel goes on it.

I can shoot sub MOA easily with my bolt guns but it took me awhile to learn how to shoot ARs accurately. I find bolt guns to be very forgiving I c an shoot them about any formI want and still get sub MOA, unless my pain is skyrocketing (8 ruptured disks plus other spine stuff). I find ARs much harder to shoot, it may just be my poor ability with ARs maybe everyone else finds them easy to shoot.

 

[para1505]

yeah fgmm 168 or 175. how crappy is the trigger? when you dry fire are you easily staying right at the center of the target at 100yds? if not, drop in a nice two stage such as geissele ssa-e. do you have a bipod on front and rear bags, is the rifle rock-solid steady before you take the shot?

Shooting on bipod rear bag have installed Larue 2 stage trigger and yes dry firing good

 

[para1505]

Have someone else shoot it, ideally someone who shoots a 308 AR well, especially if you are new to large frame ARs, this is what I recommend someone do after checking the rings and scope. Trying out FGMM is a great idea also, if it does not shoot FGMM well it probably does not shoot much of anything well. FGMM is kind of magic in how it shoots so well in so many different guns, it just works, there are many theories on why it does. I have bought a number of DPMS rifles and had mixed results now I build my own uppers than I have control over what barrel goes on it.

I can shoot sub MOA easily with my bolt guns but it took me awhile to learn how to shoot ARs accurately. I find bolt guns to be very forgiving I c an shoot them about any formI want and still get sub MOA, unless my pain is skyrocketing (8 ruptured disks plus other spine stuff). I find ARs much harder to shoot, it may just be my poor ability with ARs maybe everyone else finds them easy to shoot.

I did get some FGMM 168 today try it out tonight

 

[KAIFS]

I have a gen1 Recon - it did take a bit for it to “settle in”. After dropping in a JP single stage trigger into mine, it did improve dramatically for me. And as suggested- FGMM is very consistent and accurate load, as a matter of fact-I no longer reload or load develop for it, as there were hardly any gains compared to factory ammunition (for what I kept it for)...

 

[bfoosh006]

IMHO, 100rds may be early to decide if you have a barrel issue.. And given the reloads fired.. same thing... maybe your barrel hates CFE 223.

Try another powder as well... IMR 4895 is very forgiving... ( at least for me )

I also would tend to want to give the bore a through cleaning.

I also suggest you fire 10rds... "throwing away" the first 5 shots , then focusing on the last 5 shots... for what ever reason, I have rifles settle into the bags and the bores "settle in / season in" between ( typically different powders used, but in your case different bullets and I could be completely wrong ) different loads.

I can't prove it at all... but I have seen it consistently enough for me to "factor" that in to my results or attempts at precision.

 

[para1505]

Gonna try Varget have some. FGMM 5 round group 1.167" so might be some jope

 

[Va_Gentleman]

Mine always likes 168s ... never the 155 or 175... sub MOA on all 168

 

[para1505]

Mine always likes 168s ... never the 155 or 175... sub MOA on all 168

Might be on to something FGMM was the only 168's I've shot through it and it was it's best group

 

[bunsen27]

@para1505 Are you running a brake or adjustable gas block on this rifle?

I know my factory DPMS was very overgassed until I installed a JP adjustable gasblock and JP Cooley Comp. Now it's one of the softest shooting AR's I own. There is a LOT of mass being moved around in the AR-10/LR-308 platform and controlling that movement speed via a gas block really helps in my experience.

 

[para1505]

Think I'll try a adjustable gas block too. Besides I'm in suppressor jail so I will need one anyway I do have a JP break on it

 

[JustinReese]

Ive got the jp scs, kahntrol brake and adj gas block on mine, shoots better than my 223. Mines got the 24in barrel and it likes 168gr amax's. Im working up a new load with 168 gr bthp's and win748. Usual is varget or 4064

 

[flyer]

I'm assuming this is a DPMS G2 rifle, not LR308. Is the barrel chrome lined? Does it have a free float handguard?

If the barrel is chrome lined, that explains some of it, chrome lined barrels that shoot better than MOA are rare. If the handguard doesn't free float, the variable pressure on the barrel from shot to shot will open up groups. If you have both issues, 2" groups are about what I would expect.

 

[para1505]

I'm assuming this is a DPMS G2 rifle, not LR308. Is the barrel chrome lined? Does it have a free float handguard?

If the barrel is chrome lined, that explains some of it, chrome lined barrels that shoot better than MOA are rare. If the handguard doesn't free float, the variable pressure on the barrel from shot to shot will open up groups. If you have both issues, 2" groups are about what I would expect.

I'm not sure if its chromed line. I'm the guns 2nd owner it's a DPMS barrel 1:10 twist 18" barrel fluted. It is free floated, PRI hand guard

 

[Birddog6424]

I'm not sure if its chromed line. I'm the guns 2nd owner it's a DPMS barrel 1:10 twist 18" barrel fluted. It is free floated, PRI hand guard

It kinda sounds like their SASS.

If it is, it should be a fairly accurate rifle. Those are a fluted, 18" stainless barrel in that twist.

I have that rifle and it shoots very well. 155s and 168's are ok, but it really loves 175gr SMK's over RE15.

 

[para1505]

It kinda sounds like their SASS.

If it is, it should be a fairly accurate rifle. Those are a fluted, 18" stainless barrel in that twist.

I have that rifle and it shoots very well. 155s and 168's are ok, but it really loves 175gr SMK's over RE15.

I have some RE15 and 178 HRN 178 BTHP

 

[Birddog6424]

I have some RE15 and 178 HRN 178 BTHP

I would grab a box of Federal GMM as pointed out above. That stuff truly is amazing in nearly ever gun. See how it shoots.

Obviously go through all your troubleshooting steps of making sure everything is buttoned down. Shooting a big frame AR is a little trickier than a bolt gun, but from a solid firing position you should still see great accuracy.

If it's still a little dodgy, in your shoes I would probably scrub the barrel down since break in is now complete, see if that helps. Pull out all the copper and carbon, then shoot it some more.

Realistically, you should see better than 1 MoA. Mine is fairly consistent in the .6 to .7 range. Which is decent for a factory rifle of that nature.

Good luck with it.

 

[Birddog6424]

And how's this for funny... in the ultimate "small world" moment, I opened up my Facebook page and it showed me one of my memories post from March 6th, 2015. Apparently I was at the range at the crack of dawn to load development for my SASS.

 

[eastexsteve]

I would have to second the opinion of many here. Unless you are used to shooting AR-10 type clones, the issue may be you and not the gun or ammo. If you are new to them, they can be tricky. Especially so if they are of the lightweight variety.

Also, I would lose the bipod and any other unecessary hardware and just start out shooting over a bag/sandbag with a small bag in your support hand under the butt of the gun. Work at trying to get the gun on target and dead still. Concentrate on dry firing and follow-through.

 

[para1505]

I would have to second the opinion of many here. Unless you are used to shooting AR-10 type clones, the issue may be you and not the gun or ammo. If you are new to them, they can be tricky. Especially so if they are of the lightweight variety.

Also, I would lose the bipod and any other unecessary hardware and just start out shooting over a bag/sandbag with a small bag in your support hand under the butt of the gun. Work at trying to get the gun on target and dead still. Concentrate on dry firing and follow-through.

I'll work on your advise running this rifle.

 

[para1505]

OK fellow shooters I got it to shooting a 3/4" group using 43.1 gn Varget and 178 gn BTHP MV 2550

 

[Birddog6424]

OK fellow shooters I got it to shooting a 3/4" group using 43.1 gn Varget and 178 gn BTHP MV 2550

Great to hear it. That's right where mine is sitting, accuracy wise. Pretty good performance for that rifle.

 

[wchartz]

OK fellow shooters I got it to shooting a 3/4" group using 43.1 gn Varget and 178 gn BTHP MV 2550

I tried CFR 223 in my bolt 308 and I never saw such bad groups before, in the range of 3 MOA. Varget and 4895 gives me .75 MOA with the same bullets. Curiously enough , CFR had the smallest SD.

 

[para1505]

I tried CFR 223 in my bolt 308 and I never saw such bad groups before, in the range of 3 MOA. Varget and 4895 gives me .75 MOA with the same bullets. Curiously enough , CFR had the smallest SD.

I did a velocity ladder test with CFE 223 and still large groups with it